This set of neon-colored Bic pens have black caps and are printed with a black Apple logotype in Apple Garamond, Apple’s corporate font at the time.
The three neon colors include purple, green, and pink.
UPDATE: After I posted this originally, I discovered an eBay listing for Apple “color changing pens” that looked just like these. I tested them by grasping them for a few minutes, and found that they are, indeed, color changing with heat! I’m not sure if the effect has faded with age, but each of the three colors still fade. The last three photos show the effect.